The invention herein pertains to alarm systems, and particularly for a computer operated alarm system to prevent injury while operating machinery such as milling machines, presses, lathes, metal shears and the like.
In order to help prevent injuries to personnel in industrial environments, barrier guards have been used for many years on and around various machinery to prevent accidental body contact. Other conventional safety devices include pull-back restraints, light curtains, two hand activation switches, safety mats, photocell operated shut off switches and the like. While all of the aforementioned safety equipment is useful in particular circumstances, all have shortcomings and limitations which reduce their effectiveness. For example, the use of barrier guards and fences around equipment is often circumvented by workers for convenience. Actuation devices requiring two hands are often bypassed by overriding one or both switches. Light curtains, safety mats and the like are sometimes avoided by employees that prefer to take a risk, as opposed to utilizing the available safety features for accident prevention.
Thus, with the inconveniences and shortcomings of available safety and alarm systems well documented, the present invention was conceived and one of its objectives is to provide an alarm system and method which is versatile and can be readily adapted to any of a variety of equipment or machinery in a particular operating environment.
It is another objective of the present invention to provide an alarm system which is computer controlled and can be programmed, installed and easily adjusted as needed.
It is yet another objective of the present invention to provide an alarm system and method for preventing injury to personnel which is relatively inexpensive to purchase, setup and operate.
It is still another objective of the present invention to provide an alarm system which has a plurality of alarm zones to warn personnel by the degree of impending danger.
It is yet another objective of the present invention to provide an alarm system which can be suited to a single machinery operator or can be adjusted to encompass others that may enter a prescribed tracking zone.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is set forth below.
The alarm system and method described herein provides a tracking zone proximate selected machinery or equipment as desired. Within the tracking zone is an alarm zone whereby a transmitter as worn by, for example, a machine operator can be monitored to prevent operator injury. The preset tracking and alarm zones are defined by a trio of receivers available for signals directed from the transmitter such as worn on the arm of a machine operator. Should the operators arm penetrate a defined zone, a visual or audible alarm is activated. If the operator""s arm penetrates a final, innermost alarm zone the receivers will send signals to the system controller which will turn the power to the machinery off, thus preventing injury to the operator.
Receivers are mounted to selected machinery in a fixed manner during system setup to establish a broad tracking zone to monitor the operator""s movements. Also, the axis for a desired cylindrical alarm zone is completed in a xe2x80x9cteachingxe2x80x9d mode using a programmed interface connected to a system controller. Thus, by positioning a transmitter at one point along a desired alarm zone axis a recording of its location is made. The transmitter is repositioned and the second point along the alarm zone axis is also recorded. This location information is saved under a specific identity within the machinery description file in the database of the system controller. The setup procedure is repeated for each desired alarm zone. A secondary setup function establishes the machine center line. Transmitters positioned at the horizontal center of the machinery tracking zone allow the center line location to be recorded which is then saved in another data file of the system controller. In the method of use for specific machinery, a basic setup is completed whereby, for example multiple, concentric cylindrical alarm zones are defined within a cubical tracking zone. Once the zone geometry is set the operator can assign the available alarm devices for triggering by penetration of the transmitter of the operator as it enters the specific alarm zone, such as a flashing light for the outermost alarm zone. An audible alarm for the next or second inner alarm zone may likewise be utilized. Termination of power to the machinery is then set to prevent injury to the operator should the final or innermost alarm zone be penetrated.